Improved piers for bridges



m m i i PATENTLD JUNE zo, 1365.

um a ,m N N w LR @gaf y w. m Z T uw 5. M N L mmJ N 4UNITED-S'nn'rEs' ERAsTUs W. SMITH, on NEW Yong-N. Y. 'Y

PATENT. OFFICE.

. iMPRoyi-:p lPil-:nsf FfoR BRIDGES.

Specification formingpart of Letters Patent No. 48,317, dated'J une 20, 1865: l

To all inkom it may concern;

Y Be it known that LERAsrUs W. SMITH, of

the city and county` of New York, in theState of .New York, have invented a certain new and `useful Improvement in ythe Construction of Piers for` Bridges 'and Similar Masonry under Water; and `I do hereby declare' that the fol-` lowing isa full and exact description thereof. The accompanying' drawings form a partof thisspeciication. f My invention is intended tojbe used in that `system of construction. in which tubes or hol low cylinders of iron formed in sections orothery wise are sunkthrough the water and, to a suiiicient depthY in totheearth, and the contents cxl cavated and removed through anair-lock..

i This general methodof construction hasbeen successfullypracticed for a number ot years,

themen excavating within the tube at the` botv tcm of the waterunder a pressure of air, artificially produced, of suilicien't force to keepout l y the water and toallow the men to workunder. the same conditions,ias; regards pressuvre as wouldbe .experienced in a diving-bellat the same depth. The circuitou's processnecessary `to pass the workmen or any material through l the air-lock would inakel it very Slow and expensivefto properly fill the interior with ma.- sonary by `previously-known means. My inlvention. enables nie to eect this with little expense. l I haverapplied itin the` building ofthel -piers for the iron bridge nowin process of crec- `tionover the Harlem river.-

`Ello enable others skilled in` the art to make l and use inyinvention, I will proceed to desribe'i'he manner in which I applied it for this bridge, reference being had to the accompany- -ing drawings.

' .i Figures 1, A2, and 3 represent central vertical sections of theen tirestructure. sents acorrespondingsection, on alarger scale, l ofthe base portion, to whiclrm'y inventionlmore `specifically relates. Fig'. 1 represents the condition of thepier w-henthesinking of the`sbell `or tube-andthe excavatingfthe earth at the base has been completed. Fig. 2 represents the condition whenthe stones have been packed in the bottom and the insterstices filled in accordance with my invention. Y Fig. 3 represents the condition after the compressed air inV the pier has been allowedto escape and the air-* Fig. 4 reprel .ofthe structure perfectly tight.

lock has been removed to allow free access for l the completion ofrthemasonry.. A A, &c., are thin cylindrical shells of castiron, each six feet indiameter and two inches thick.- Flauges a a are formed on the interior f offeach,and' by means of screw-bolts (not rep'- resented) these flanges are secured firmly together, and the joint between-ismadetight by red-lead putty. The length of each section is ninefeet, and the -bottom of the lower one is made withouta flange and is'sharpened, as rep resented, to allow it' to' more readily sink into* theearth as the -interior is excavated.

An air-lock, B, ssecuredon the top of the uppermost section, provided with double doors b '11', and Withseveral cocks, and a windlass required to allowremoving. the earth during the excavating process, and the introduction of stime and other material during. the early portion ot' the fillingv process." .All these parts were constructedand operated jin `the previously known and approved manuel'.

After a sectional pileor shell, A A, Src., hadv been sunk, and the intcriorearthremoved to' a sufficient depth`t0 reach a hard and reliable foundation, the `process` `ot' removingearth was discontinued, and while the pressure ot' air was maintained Va Vquantity otf stone, C C, was laid as tirml y as was practicable, filling the bottom of thelowermost section, A. 'Iheinterstices f in the mass of stone bein gl empty, or filled only with air, 4(by reasonot' the pressure of the air within the shell being suliicient to keep the water excluded a suflicient quantityotffreshly-l mixed plaster, D, otherwise known as "gyp sum,7 p sulphate oflime, or plaster-of-paris,

was then poureddovvnvv upon the massltoillf.

the interstices completely. This material sets with great rapidity, and in doing so expands orswells slightly, so that .the mass is found,

after a very brietl period, to make the bottom Its .tenacity is Valso such that a layer o t' considerablyless height than one section, A, I found to'be sufiicient to resist `the entire pressure ot the wa-` iter. It will be understood that by building up this foundation of'plasterwork quite to the lower face of the'lowermos'tlange, a, I secure fthe aid of the said `flange to prevent the slid?` .ling upward of the entire 'mass bodlily, in .obe-

dience to the pressure of the water below.

2 i taartv up the plaster-Work to that height, or, better perhaps, to introduce a separate ange or internal projection at a 'lower level in the lowermost section,as indicated by the red outline d; but I have ascertained by actual experiment that the work can be de-.

pended upon to adhere to the interior ot' the section with sufficient force .to preventits displacement,y even if no such vflange or projection Was'made available. After the grouting' with plaster had, been successfully effected, I

allowed the extra pressure ot' air in the space above to be relieved by opening a suitable passage, and proceeded to remove the airlock B altogether. This operation opened .the interior of :thepile tofree access by ordinary means, land l: proceed lthen to build upV` withv all the'deliberation and skill which may be required, and fill `up the pile or `series of' sections with well-laid masonry, bedding each stone properlyin hydraulic cement and allowing the latter to become thoroughly set. The exterior of this mason-ry, ot'- course, applies against the ipsideof theshell A, and eachaids to support theother so long 'as both remain.

Whenever, in consequenceof oxidation or other,

causes, theiron shell becomes removed in whole or in part,'a complete internal pier of masonry'is developed, planted deeply and securelyn the earth, and capable of withstanding` alone all the strains'to which itis likely to be exposed.

Concrete has been roughly introducedas a tilling for piers of this character previous to my invention. This material formed a Weak mass, .but mine torms a strong one.

My method of grouting, in the-manner and with thefmateri-al described, between previously-compacted vpieces ot' stone,V makes so.

strong a stopping or sealing of the bottom of,

the case A that a layer ofonlya few feet thick vresists an upward pressure due to a head et' fty feet of water.y This subsequently becomes a substantial portion ofthe Work, and does not extend to such a height but `that the superinwith W-ater.

bridge, above referred'to but the plaster may -euinbent well-laid ymast'nry is rmlygplantedl deep in the bottom of thel river, and able generally tol maintain itself independently of any considerable reliance on the work below.

I prefer to lay the stones C regularly as well as compactl y, and to employ, when practicable,

stones that are prepared by hewing or otherwise, so as to form -very good joints. 'In applying the stones together I leave a considerable space between the several stones, s'o that there shall be widevertical joints to belled with the grout, in order that the expansionof the latter therein, and consequently the tenden cy ofthe entire massto expandlaterally in alldirections, may be veryap'preciable; but I make the horizontal joints as close as possible, because any expansion in a vertical directionV i Willinot contribute to tighten the union of the stopping with the case, but might under some circumstances be disadvantageous.

I can use the plastersuecessfullymxedalone l t was so in troducedat the Harlem be-mixed`in any desired proportions with thin hydraulic mortar if desired, andthe compoundv groutthns formed may be used'in the manner above described.

Having'now fully described my Letters Paten t, is-

1. The employment of calcined plaster, or equivalent expansive material, in sealing orl stopping the bottom of hollow piers or shells'` for submarinel masonry, substantially inf'th'e manner and for the purpose herein set forth.'vv

2. Stopping the bottom ot' such shellsf'by grouting or flowing the calcined plaster 'or an# alog'ous semi-fluid material into interstices in previouslylaid stone, substantially in the manner and torvthe purpose herein set forth.'

. ERASTUS W. SMITH.

Witnesses:

THOMAS D. STETs'oN, S. W. BURNHAM.

inventiol i, y l what I claim as new, and desire to secure by. 

